Patent Document 1 discloses a film cooling structure in which blow holes (film cooling holes) are formed on a wall surface of a rotor blade of a gas turbine or of a liner of a combustor, wherein the wall surface faces high-temperature gas (heating medium), and a cooling medium blown from the blow holes flows along the wall surface so as to cool the wall surface. In this film cooling structure, in order to suppress the separation of the cooling medium from the wall surface and to improve a film efficiency, blowing directions of cooling media from one pair or more pairs of blow holes are set so as to form swirls in directions in which the cooling media are mutually pressed against the wall surface.
Specifically, each pair of blow holes are arranged on the wall surface back and forth in a flow direction of high-temperature gas, and each blow hole is formed on the wall surface into an elliptical shape whose long axis is in the blowing direction of a cooling medium therefrom. Blowing speed vectors of the cooling media blown from the pair of blow holes have transverse angle components β1 and β2 on a plane along the wall surface with respect to the flow direction of the high-temperature gas, and the transverse angle components β1 and β2 are set to be different from each other.